New Flu Guidelines Seek to Improve Vaccination Rates

Author: Stephanie R. Thune, PharmD

Dr. Thune is an assistant professor of
pharmacy practice at Midwestern
University College of Pharmacy,
Glendale, Ariz.

With daily updates about the
potential avian influenza pandemic
in the mass media, it
seems that standard seasonal influenza
(flu) is no more serious than the common
cold. The flu can be responsible for significant
morbidity and mortality, however.
Now that the flu season is upon us, it is
important to keep abreast of practice
changes and updates on the prevention
and treatment of the flu. It should be a
concern in all pharmacists' practices
regardless of their specialty or practice
site. From geriatrics to pediatrics, acute
care to ambulatory care, few disease
states are as omnipresent as the flu.

A Look Back on the 2006-2007 Influenza Season

The 2006-2007 flu season had the lowest
rate of mortality and pediatric hospitalizations
in the last 3 flu seasons. The
flu season peaked in February, but it
remained well below epidemic thresholds.
As with other flu seasons, the
influenza A virus (mostly H3 and H1) was
much more commonly isolated than
influenza B.1

Despite the good news about last
year's flu season, the rate of pediatric
influenza-related deaths and coinfections
with Staphylococcus aureus has
increased. Sixty-eight deaths occurred
from October 2006 to May 2007. During
the 2004-2005 flu season, one S aureus
coinfection was reported among pediatric
deaths. The number rose sharply to
21 during the 2006-2007 season.

Another upsetting trend seen in pediatric
patients during the 2006-2007 flu
season is the apparent lack of vaccination
adherence. Although vaccination
status was unknown for 15 of the 68
pediatric patients who died, the remaining
53 had a vaccination rate of 6%.1

Vaccination Recommendations

Two types of flu vaccines are currently
available on the market: the live attenuated
intranasal vaccine (LAIV) and the
trivalent inactivated vaccine (TIV), which
is typically administered intramuscularly.
Viral components of both vaccines are
grown in eggs, so the vaccine should be
avoided in patients with egg allergies. If
the vaccine is absolutely necessary,
desensitization protocols can be used.
The LAIV, like other live vaccines, should
be avoided in immunocompromised
patients.2

The Centers for Disease Control and
Prevention (CDC) and the World Health
Organization identify the virus isolates
during each flu season, and the Vaccine
and Related Biologics Advisory
Committee of the FDA is charged with
selecting the components of that year's
flu vaccine. This year, the vaccine was
modified to update the influenza A
(H1N1) component to make it similar to
the virus antigen often isolated in the
2006-2007 season.1

The CDC's Advisory
Committee on Immunization
Practices published
new guidelines for
the administration of the
flu vaccine in June 2007.
The changes focus on
pediatric patients, improvement
of vaccination
rates, and health care
personnel.2

The new guidelines
stress the importance of
using double vaccination
in children who have not
been previously vaccinated
against the flu or who
have received only 1
dose in the previous year.
The TIV requires that the
2 doses be separated by
4 weeks, and 6 weeks'
separation is necessary
for LAIV. There is no preference
for either type of vaccine in pediatrics;
however, the LAIV is FDA-approved
in children ≥5 years of age. After
a child is treated with 2 flu vaccine
doses in 1 year, the child may receive 1
dose annually.3

The American Academy of Pediatrics
(AAP) also published guidelines in 2007
addressing the prevention of influenza.
AAP recommends that any contacts with
infants not old enough to be vaccinated
(<6 months) should be immunized. The
recommendation is also true for caregivers
and contacts for all children <5
years and any children who are at high
risk from influenza complications.4

Pharmacists who are vaccine providers
will be encouraged by the CDC's
recommendation that the flu vaccine be
offered during flu-season health care visits.
The guidelines also state that providers
should offer vaccination clinics
throughout the flu season in order to
increase the vaccinated population.

Vaccination rates are lower than
desired, especially for at-risk populations.
Elderly patients (>65 years of age) have
the highest rate of mortality during influenza
epidemics.5 The 2005 vaccination
rate for these patients was 59.6%.2 This
number is desirable when contrasted
with another at-risk group, pregnant women,
whose 2005 rate was only 15.6%.2

The focus on health care personnel
vaccination stems from their exposure to
high-risk individuals. It is important that
both patients and caregivers be vaccinated
to prevent spread from one population
to the other. About 33% of health
care personnel were immunized against
the flu in 2005. Because of this low number,
the CDC recommends that health
care institutions use flu-vaccination status
as a quality marker for infection control.
They suggest signed documents of
refusal be obtained from health care personnel
who choose not to be vaccinated.2

Antiviral Treatment

Two groups of antiviral medications
have been used to combat flu symptoms
and prevent exposure: the neuraminidase
inhibitors (NAIs; oseltamivir and
zanamivir) and the adamantanes (amantadine
and rimantadine). The NAIs are
newer to the market, introduced within
the last decade. Amantadine has been
available since the early 1980s as an anti-
Parkinson's agent.

The CDC discourages using the
adamantanes for treatment or prophylaxis
against the flu because of increasing
resistance to current influenza A
strains.2 When antiviral treatment or prophylaxis
is required, the NAIs are the
drug of choice. It is important to note that
antiviral medications should be avoided
within 2 weeks of receiving the LAIV
because the antivirals can decrease the
effectiveness of the vaccine.6-8 The medications
should be started within 48
hours of the appearance of symptoms
for greatest effectiveness.7,8

Zanamivir (Relenza) is an inhaled NAI
used twice daily for 5 days for treatment
and 10 days for prophylaxis of the seasonal
flu. It is indicated for adults and
children =5 years of age. Because of its
unique Diskhaler delivery system, it is
important that patients receive adequate
counseling to ensure proper use. Zanamivir
should not be used in patients
with chronic obstructive pulmonary disease,
asthma, or any other underlying
respiratory diseases with the potential
for bronchospasm. Headache is the most
common adverse effect.7

Oseltamivir (Tamiflu), the more popular
NAI, is available as a 75-mg capsule and
60-mg/5-mL suspension and is indicated
for the treatment and prophylaxis of seasonal
flu in adults and children ≥12
months of age (see Table for dosing).
Oseltamivir, compared with placebo, was
also shown to decrease the occurrence
of acute otitis media in children aged 1 to
12 years.9 In contrast to the inhaled
zanamivir, the most common adverse
effect of oseltamivir is gastrointestinal
disturbances. A Dear Health Care
Professional letter was issued in
November 2006 concerning recent safety
data monitored by the FDA. There
have been a small number of cases of
central nervous system disturbances
resulting in self-injury and delirium after
receipt of the drug. This effect is more
common in pediatric patients in Japan,
where consumption of oseltamivir is
much higher than in the United States.8

Conclusion

The seasonal flu is a concern to any
pharmacist who provides patient care in
any type of setting. Ambulatory pharmacists
can improve vaccine adherence by
offering vaccination clinics and counseling
patients on pharmacologic supportive
care to treat symptoms as well as
important nonpharmaceutical interventions
that can help prevent the spread of
the virus. Pharmacists in health systems
practice can partner with other disciplines
to improve patient safety by
ensuring all health care personnel
receive the flu vaccine and designing
vaccination pathways to make sure all
patients are discharged with proper
immunizations during the flu season.